How Fasteners Are Made紧固件是怎样制造的

From wire rod to finished fastener从盘条到成品

1. Wire rod盘条Hot-rolled steel coil of the selected grade按所选钢种采购的热轧线材
2. Annealing & surface preparation退火与表面准备Softening (for alloy steels) and a lubricating coating for drawing and forming合金钢需退火软化，并做润滑涂层以便拉拔和成型
3. Wire drawing拉丝Drawn to an accurate diameter拉拔到精确的线径
4. Cold heading冷镦Multi-station headers cut the wire and form the head and shank at high speed多工位冷镦机切料，并高速成型头部和杆部
5. Trimming / pointing切边 / 打尖Hex heads trimmed, points formed where needed切出六角头，需要时成型尾部
6. Thread rolling搓丝 / 滚丝Threads formed between dies by rolling, not cutting螺纹在模具间滚压成型，而非切削
7. Heat treatment热处理Quench and temper, or case hardening调质或渗碳淬火
8. Surface treatment表面处理Plating or coating电镀或涂覆
9. Inspection & sorting检验与筛选Dimensional, mechanical and visual checks; optical sorting尺寸、力学性能和外观检验；光学筛选
10. Packing包装Labelled for traceability贴标包装，可追溯

Why cold heading and rolled threads为什么采用冷镦和滚压螺纹

• Material is shaped, not cut away, so waste is very low and output is high材料是被“挤”成形，而不是被切除，材料利用率高、效率高
• The steel grain flow follows the shape of the head and thread instead of being cut through, which improves strength and fatigue life金属纤维沿头部和螺纹的轮廓连续分布，不被切断，强度和疲劳寿命更好
• Rolled threads are work-hardened at the root. For fatigue-critical high-strength bolts, rolling after heat treatment further improves fatigue strength滚压螺纹牙底经过加工硬化。对疲劳要求高的高强度螺栓，热处理后再滚丝可进一步提高疲劳强度

Other processes其它工艺

• Hot forging — for large diameters and long bolts热锻：用于大规格和长螺栓
• CNC and automatic-lathe turning — for special parts, inserts and small batches that cannot be headed economically数控车床、自动车床车削：用于特殊零件、嵌件以及不适合冷镦的小批量产品
• Stamping — for washers, clips and flat parts冲压：用于垫圈、卡片和各类平板件

Quality points to watch需要关注的质量要点

• Head cracks and seams from the wire rod or forming盘条缺陷或成型造成的头部裂纹、折叠
• Thread laps and incomplete threads螺纹折叠、牙型不完整
• Surface decarburization and incorrect hardness after heat treatment热处理后表面脱碳、硬度不合格
• Mixed parts — prevented by line clearance and 100% optical sorting where needed混料——通过清线管理和必要时的 100% 光学筛选来防止

Our Suzhou factory combines automatic lathes, CCD optical sorting and an in-house inspection laboratory — see Manufacturing & Quality制造与质量.我们的苏州工厂配备自动车床、CCD 光学筛选和检测实验室，详见Manufacturing & Quality制造与质量。